Device for moving a stack of products using a robot

ABSTRACT

A device for moving a stack of products using a robot. The robot has an articulated arm and a first gripper for the stack of products. The first gripper is disposed on the articulated arm. A gripping device is disposed on the articulated arm, the gripping device contains the first gripper and a second gripper, the first and second grippers are positionable relative to one another. Robot advantageously provides a method of moving stacks of products in an automated way and in particular of depositing them in a turned or unturned arrangement.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority, under 35 U.S.C. § 119, of Germanpatent application DE 10 2020 201 669.0, filed Feb. 11, 2020; the priorapplication is herewith incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION Field of the Invention

The invention relates to a device that has the features described in thepreamble of the independent claim.

The technical field of the invention is the graphic industry and inparticular the field of handling (e.g. gripping, holding, moving,rotating, turning and/or depositing) stacks of products, preferablystacks of printed and folded flat products, preferably made of paper,board, metal, or a composite material, by a manipulator, in particular arobot or an articulated robot.

It is known manually to transport stacks of products such as foldedsignatures from the delivery of a machine for further processing such asa folder to a pallet and to deposit them there in accordance with aknown deposit scheme. This task puts a lot of strain on the body becausefour to five stacks of products need to be moved per minute. It is alsoknown to use an articulated robot for this purpose, for instance aproduct called “CoBo-Stack” manufactured by MBO Maschinenbau OppenweilerBinder GmbH & Co. KG based in Oppenweiler, Germany.

In FIG. 11a , of Japanese patent application JPS6048848A disclosesgripping a stack of products at diagonally opposite corners and in FIG.9, the document discloses a sagging of the stack. The two illustratedgrippers belong to two separate robots.

U.S. patent publication No. 2006263196A1 discloses to rotate and turn astack by means of a robot gripper.

European patent EP1645434B1, corresponding to U.S. Pat. No. 7,607,882,discloses to pivot a stack of products into an upright position and totransfer the stack of products to a clamp/to grip the stack of productsfrom above.

Published, European patent application EP2128056A1 discloses a robotwith an articulated arm for handling a stack and, in FIG. 4, a grippingdevice.

German utility model DE202019106975U1, corresponding to U.S. patentpublication No. 2020/0354167, discloses a handling device fortransferring a stack of products, the handling device containing agripping unit movable in three dimensions. The gripper unit containsfirst and second lateral faces and a respective upper and lower holdingelement supported for linear movement along a respective lateral face.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide an improvement over theprior art in particular in such a way that stacks of products may bemoved in an automated way and deposited, in particular in a turned orunturned arrangement.

In accordance with the invention, this object is attained by the devicerecited in the independent claim.

Advantageous and thus preferred further developments of the inventionwill become apparent from the dependent claims as well as from thedescription and drawings.

The present invention relates to a device for moving a stack of productsusing a robot, wherein the robot comprises an articulated arm and afirst gripper for the stack of products disposed on the articulated arm.The device is characterized in that a gripping device containing thefirst gripper and a second gripper is disposed on the articulated arm,the first gripper and the second gripper being positionable relative toone another.

The device as such or the use thereof advantageously provides a way ofmoving stacks of products in an automated way, in particular to depositthem in a turned or unturned arrangement.

A particular advantage may be considered to be that stacks of productsof different sizes or formats may be moved and in particular selectivelydeposited in a turned or unturned arrangement.

“Selectively” is understood to mean that the stack of products is eitherturned or is not turned. The selection may preferably be made by adigital computer, in particular as a function of what is known as adeposit scheme. “Selectively” is further understood to indicate that themethod may be carried out multiple successive times with respectivestacks of products and that in the process, at least one stack ofproducts is turned and at least one stack of products is not turned.

The following paragraphs describe preferred further developments of theinvention (in short: further developments).

A further development may be characterized in that the two grippers arepositionable, preferably in a computer-controlled way, to accommodatepredefined formats of products or stacks of products. The grippers maybe movable, preferably linearly movable, for positioning purposes. Thepositioning is preferably computer-controlled.

A further development may be characterized in that the two grippers arepositionable on the two ends of a selected diagonal of a selectedformat. The positioning is preferably computer-controlled.

A further development may be characterized in that the first gripper isconfigured

as a first pliers-type gripper with a first pair of gripper jaws and thesecond gripper is configured as a second pliers-type gripper with asecond pair of gripper jaws.

A further development may be characterized in that each one of the twopairs of gripper jaws contains an immovable gripper jaw and a movablegripper jaw that is linearly movable relative to the immovable gripperjaw. Linear drives may be provided, preferably electric linear driveswith threaded spindles. Of course, the immovable gripper jaws are nottotally immovable they may be moved by the motion of the robot, of thegripping device and/or of the grippers. The immovable gripper jaws areonly unmoved or only negligibly moved relative to the movable gripperjaws when the grippers open and close.

A further development may be characterized in that each one of theimmovable gripper jaws contains a support element extending in ahorizontal direction and at least one stop element extending in avertical direction.

A further development may be characterized in that each one of theimmovable gripper jaws contains a support pad extending in a horizontaldirection as the support element and two stop surfaces extending in avertical direction and perpendicular to one another as stop elements.All surfaces may be perpendicular to one another.

A further development may be characterized in that the stack of productsis held in a form/-fitting/positive and/or friction-fitting/non-positiveway during the movement.

A further development may be characterized in that at least one blowerdevice is disposed on the gripping device to blow air under the stack ofproducts when the stack of products is deposited.

A further development may be characterized in that at least one furthergripper is disposed on the gripping device, the further gripper designedas a suction gripper for intermediate layers. For suction-based grippingand holding, suction air may be applied to the suction gripper in acomputer-controlled way.

A further development may be characterized in that at least one distancesensor and/or at least one camera is provided on the gripping device.

A further development may be characterized in that the gripping devicecontains a first support arm and the first gripper is disposed on thefirst support arm for linear movement in the longitudinal directionthereof.

A further development may be characterized in that the gripping devicecomprises a second support arm and the second gripper is disposed on thesecond support arm for linear movement in the longitudinal directionthereof.

A linear drive, preferably an electric linear drive with a threadedspindle, may be provided on the support arm to move the grippers alongthe support arms. The linear drive may be electric. The support arm mayhave a length correlating with a maximum-format stack of products to bemoved.

A further development may be characterized in that the first support armand the second support arm are disposed on the gripping device so as tobe perpendicular to one another. The support arms may form an X-Y axissystem for format-adjustable grippers. Movable gripper jaws of thegrippers may form the Z axis that is perpendicular thereto.

A further development may be characterized in that the two linearlymovable gripper jaws are movable in a direction perpendicular to therespective support arm.

A further development may be characterized in that the gripping deviceis disposed on the robot arm so as to be rotatable about an axis ofrotation. The axis of rotation is preferably for rotating the stack ofproducts about a vertical axis and/or for depositing a stack of productsthat has been rotated in the horizontal.

A further development may be characterized in that the gripping deviceis disposed on the robot arm so as to be pivotable about a pivot axisperpendicular to the axis of rotation. The pivot axis is preferably forpivoting the stack of products about a horizontal axis and/or fordepositing a stack of products that has selectively been turned or notturned relative to the horizontal.

A further development may be characterized in that the articulated armhas six axes, preferably axes of rotation.

A further development may be characterized in that the robot ishorizontally displaceable, for instance on rails or rollers, relative toone or more machines for further processing that create stacks ofproducts.

In any desired combination with one another, the features andcombinations of features described in the above sections TechnicalField, Invention, and in the various sections above on furtherdevelopments as well as in the following section Exemplary Embodimentsrepresent further advantageous further developments of the invention.

Special Further Developments Pertaining to the Pivoting Movement

Further developments may be characterized in that the device is usedand/or configured to implement the following methods.

A method of moving a stack of products using a robot, wherein the robotcomprises the articulated arm and at least the two grippers disposed onthe articulated arm to grip the stack of products and wherein the stackof products is selectively turned comprises the steps of pivoting thestack of products through an effective angle α1< >180° and subsequentlypivoting the stack through an effective angle α2=180°−α1 or pivoting thestack back through an effective angle α2=−α1.

The stack of products is advantageously pivoted in two steps andselectively turned in this process. In a first step, it is pivotedthrough an effective angle α1< >180°. A second pivoting step is throughan effective angle α2=180°−α1. If α1 and α2 both equal 90°, for example,a turn through 180° is made. If α1 and α2 are 90° and −90°, forinstance, no turn is made.

The two-step pivoting process of the invention advantageously providesan opportunity to introduce intermediate steps such as vibrating orstraightening the edges of the stack of products. In addition, thetwo-step pivoting process of the invention makes it possible to carryout the two steps at different positions, for instance in that the robotcarries out a movement in between. In addition, the two-step pivotingprocess of the invention advantageously allows the two steps to becarried out by different devices, for instance the robot and a pivotingdevice that is different from the robot.

The “effective angle” is understood to indicate that the angle isindependent of the type of the pivoting movement. An effective angle of+90° may therefore be attained by a pivoting movement through 90°, twopivoting movements through +45° each, or a pivoting movement through−270°. Instead of “effective angle”, just the term “angle” may be used.

A further development of the invention may be characterized in that thepivoting through the effective angle α1 is achieved by a pivoting devicedifferent from the robot. The pivoting device may be assigned to adelivery of a machine for further processing, in particular a folder,and may in particular be disposed thereon. It may comprise a pivotablegripper for the stack of products. The pivoting device may be controlledby a digital computer. The pivoting device preferably pivots the stackof products through α1=90°.

A further development may be characterized in that the step of pivotingthrough the effective angle α1 occurs before the step of moving, i.e. inthat the step of moving starts from the pivoted position of the stack ofproducts. The movement is preferably achieved by the robot arm.

A further development may be characterized in that the step of pivotingthrough the effective angle α1 occurs about a horizontal axis. The axismay be aligned to be parallel with the direction of transport of adelivery of a machine for further processing, in particular a folder.Before it is pivoted, the stack of products is preferably gripped andheld.

A further development may be characterized in that when the stack ofproducts is pivoted through the effective angle α1, it is pivoted out ofa horizontal position. In the horizontal position, the individualproducts, for instance folded signatures, in the stack of products arepreferably horizontal.

A further development may be characterized in that when the stack ofproducts is pivoted through the effective angle α1, it is pivoted into avertical position. In the vertical position, the individual products inthe stack of products are preferably upright.

A further development may be characterized in that the stack of productsis aligned and/or straightened in one direction and/or straightened intwo directions perpendicular to one another and/or vibrated and/oraerated when it is not in a horizontal position and/or in that afanned-out stack of products is transformed into an unfanned stack(“unfanning”). During this process, the stack of products may be in thepivoting device, e.g. in the gripper thereof. The gripper may beslightly open in particular for aeration. A straightening and/orunfanning device may comprise two vertical surfaces, for instanceplates, preferably with lateral chamfers, that are movable relative toone another. This device may be open before the pivoting step and closedafter the pivoting step. For this purpose, the surfaces may be movedtowards and away from one another. Pneumatic cylinders may be providedto create the vibration. Finally the device/the surfaces thereofpreferably move into an open position for the stack of products to betaken over.

A further development may be characterized in that in the verticalposition, the stack of products is turned about a vertical axis,preferably by 180°. This advantageously allows the stack of products inthe vertical position to be gripped from the same side both when it isselectively turned and when it is selectively not turned. The rotatingmay be done by the pivoting device. For this purpose, the pivotingdevice may have a rotary drive. The rotary drive may be controlled by adigital computer.

A further development may be characterized in that when the stack ofproducts is turned, it is taken over from one side of the stack ofproducts and when the stack of products is not turned, it is taken overfrom the same side of the stack of products. The takeover from the oneside or from the other side may be carried out by an articulated arm ofthe robot. The selection may be computer-controlled. In this process, apredefined deposit scheme may be taken into consideration.

A further development may be characterized in that the robot takes overthe stack of products in the vertical position. The robot and inparticular the gripper thereof may be moved towards the stack ofproducts in a computer-controlled way, for instance from above and/orfrom one side.

A further development may be characterized in that the stack of productsis moved in the vertical position, at least in a path section of themovement. The position of the stack of products may be changed along thepath of the movement, for instance by pivoting it (about a horizontalaxis) and/or by rotating it (about a vertical axis).

A further development may be characterized in that the robot takes overthe stack of products from the pivoting device and moves it. The stackof products may be taken over and held by a gripping device of therobot. The movement may be achieved by moving an articulated arm of therobot. The robot may additionally be displaced in a horizontaldirection. All actions of the robot may preferably becomputer-controlled.

A further development may be characterized in that when the stack ofproducts is turned, it is taken over from one side of the stack ofproducts and when the stack of products is not turned, it is taken overfrom the opposite side of the stack of products. The takeover from theone side or from the other side may be carried out by an articulated armof the robot. In this process, a gripping device of the robot may berotated in such a way that a gripping action occurs from the one side orfrom the other side. The selection may be computer-controlled. In thisprocess, a predefined deposit scheme may be taken into consideration.

A further development may be characterized in that the pivoting throughthe effective angle α2 occurs during the movement or in between twomovement portions or after the movement. The pivoting movement may becomputer-controlled. In this process, a predefined deposit scheme may betaken into consideration.

A further development may be characterized in that the pivoting throughthe effective angle α2, a predefined deposition scheme may be taken intoconsideration. The pivoting movement may be achieved by a correspondingmovement of an articulated arm of the robot and/or by a pivoting deviceon the robot/on the articulated arm thereof and/or by a pivotablegripping device on the robot/the articulated arm thereof. The pivotingmovement may be computer-controlled.

A further development may be characterized in that when the stack ofproducts is pivoted through the effective angle α2, it is pivoted backinto a horizontal position. In this case, the stack of products is notturned, i.e. it is deposited unturned.

A further development may be characterized in that the stack of productsis deposited in the horizontal position. The stack is preferablydeposited on a pallet. To deposit the stack, grippers on the robot maysimultaneously or successively be opened and moved away laterally.

A further development may be characterized in that before the stack ofproducts is deposited, it is rotated about a vertical axis. This allowsthe alignment of the stack of products in the horizontal to be modified,for instance effectively by 90° or 180°. The rotation may becomputer-controlled. In this process, a predefined deposit scheme may betaken into consideration.

A further development may be characterized in that the effective angleα1 equals 90° and the effective angle α2 equals 90° and that the stackis pivoted further through α2. When the stack is pivoted further, thepivoting movement through al and the pivoting movement through α2preferably occur in the same pivoting direction. In this process, thetotal effect is that the stack of products is turned.

A further development may be characterized in that the effective angleα1 equals 90° and the effective angle α2 equals −90° and that the stackis pivoted back through α2. When the stack is pivoted back, the pivotingmovement through al and the pivoting movement through α2 preferablyoccur in opposite pivoting directions. In this process, the total effectis that the stack of products is not turned.

A further development may be characterized in that the stack of productsis held by at least two grippers during the movement.

A further development may be characterized in that the stack of productsis held in a form-fitting/positive and/or force-fitting/non-positive wayduring the movement.

A further development may be characterized in that one side of the stackof products has at least four corners and in that the stack of productsis held at diagonally opposite corners during the movement. If there aremore than four corners, edges may be selected that are spaced apart by alarge distance and/or are spaced apart in a way that is a goodapproximation to being diagonally opposite each other.

A further development may be characterized in that selectively, twodiagonally opposite corners or two other diagonally opposite corners areheld. The selection of the corners may be computer-controlled. In thisprocess, a predefined deposit scheme may be taken into consideration.For this purpose, a gripping device on the robot arm is preferablyrotated.

A further development may be characterized in that the stack of productsis held in such a way that the stack of products sags. For this purpose,the distance of grippers of the robot may be reduced, preferably in acomputer-controlled way, until a desired or predefined sag is attained.The stack of products may be formed of folded paper sheets.

A further development may be characterized in that the stack of productsis held in such a way that the stack of products sags diagonally. Inthis way, the stack of products with the diagonal as its “lowest point”may be deposited in a controlled and self-fixing way. For this purpose,the stack of products may be held on diagonally opposite corners.

Special Further Developments Pertaining to Stack Deposition

Further Developments may be characterized in that the device is usedand/or configured to implement the following methods.

A further development may be characterized in that the movement isterminated at a selected deposit position among multiple depositpositions of a predefined deposit scheme. The deposit scheme may besaved on a digital computer or on a network connected thereto. Aplurality of deposit schemes may be saved, for instance in a database.The selection of the deposit position (and/or a succession of depositpositions for stacks of products to be moved in succession) may becomputer-controlled. When a transport stack is built up out of stacks ofproducts, a deposit scheme may be selected for every horizontal layer;in particular, different deposit schemes may be selected for twosuccessive layers.

A further development may be characterized in that the stack of productsis deposited at the selected deposit position on a base, preferably apallet.

A further development may be characterized in that the stack of productsis held in such a way that the stack of products sags diagonally andthat when the stack that sags diagonally is deposited, the saggingportion is the first to touch the base.

A further development may be characterized in that the deposit scheme issaved on a digital computer or downloaded to the digital computer fromanother computer via a network and in that the movement is controlled bythe digital computer.

A further development may be characterized in that the deposit scheme iscalculated and/or selected by the digital computer as a function of atleast one of the following parameters: dimensions of the stack ofproducts; dimensions of the base; in a case in which the stack ofproducts is a stack of folded products: position of the folding edgesrelative to the base and/or structure of the folding edges as a functionof the type of fold.

A further development may be characterized in that multiple stacks ofproducts are successively moved, selectively turned, selectively rotatedin the horizontal, and deposited at respective selected depositpositions among multiple deposit positions of the predefined depositscheme. In this process, a computer-controlled robot with an articulatedarm and a gripping device may be used.

Special Further Developments Pertaining to the Gripping Operation

Further developments may be characterized in that the device is usedand/or configured for implementing the following methods.

A further development may be characterized in that two grippers are usedand that when the stack of products is deposited, the grippers areremoved from the stack of products in the horizontal in two directionsperpendicular to one another.

A further development may be characterized in that when the stack ofproducts is deposited, the grippers open in the vertical. In thisprocess, a gripper jaw of the gripper may be moved; preferably, agripper jaw located above the stack of products may be moved upward. Theother gripper jaw, preferably the one underneath the stack of products,may be unmoved.

A further development may be characterized in that every stack ofproducts is moved to a respective deposit position of the depositscheme, the respective deposit position selected in such a way that inthe deposit position, the grippers are removed from the stack ofproducts in the horizontal and without collision with stacks of productsthat have already been deposited.

Further Developments

Further developments may be characterized in that the device is usedand/or configured to implement the following methods.

A further development may be characterized in that the movement of thestack of products occurs from a delivery of a machine for the furtherprocessing to a pallet or to one of several pallets. In the latter case,non-stop operation is possible.

A further development may be characterized in that the movement of thestack of products occurs from a delivery of a machine for the furtherprocessing of printed products, for instance a folder, a saddlestitcher, or a perfect binder, to a pallet or to one of several pallets.

A further development may be characterized in that the stacks ofproducts in the delivery are transported in a direction of transport andare separated from one another in the direction of transport. Thetransport may occur on a roller-type conveyor. For the separation,individual drivable rollers may be driven or stopped in an appropriateway.

A further development may be characterized in that the robot is movableand usable in multiple positions of a machine for further processing oron multiple machines for further processing. For this purpose, the robotmay be supported on rollers and/or rails.

A further development may be characterized in that the stack of productsis formed of folded and/or die-cut printed products.

A further development may be characterized in that multiple stacks ofproducts are stacked on top of one another to be horizontally offsetrelative to one another and in multiple horizontal planes above oneanother to form a transport stack on a transport pallet or in that atransport stack is formed or built up in a corresponding way. Theselection of the offset and/or of the planes may be computer-controlled.In this process, a predefined deposit scheme may be taken intoconsideration.

A further development may be characterized in that a sensor disposed onthe robot detects the height of the transport stack. The sensor may bedisposed on a gripping device of the robot. Multiple sensors may beprovided. The height may be determined in absolute terms, for instancemeasured from the upper edge of a pallet or floor, or in relative termsas a distance to the sensor.

A further development may be characterized in that the height isdetected as a single height value, a number of height values at varioushorizontal positions, or a height profile.

A further development may be characterized in that the sensor isembodied as a distance sensor for measuring the height or as a camerawith digital image processing to calculate the height on the basis ofthe camera image.

A further development may be characterized in that the robot arm ismoved without collision over a transport stack that has only partly beenbuilt up and in that the digital computer factors in the detected heightas it controls the movement of the robot arm.

A further development may be characterized in that the robot takesindividual intermediate layers off of a stack and deposits them onrespective planes. The intermediate layers may be made of cardboard. Thedeposit of intermediate layers may be computer-controlled. In thisprocess, a predefined deposit scheme and/or stacking scheme may be takeninto consideration.

A further development may be characterized in that the intermediatelayer is held by suction. For this purpose, a suction gripper may bedisposed on a gripping device of the robot. A number of such suctiongrippers may be used.

A further development may be characterized in that the movement is donein a fully automated way, as a function of a selected deposit schemeand/or stacking scheme and in a way adapted to the production speed atleast of the machine for further processing.

A further development may be characterized in that the movement of therobot arm occurs in a protected area.

A further development may be characterized in that to create theprotected area, a housing and/or a fence and/or a light barrier and/or amonitoring camera is used.

Alternatives

As an alternative to the aforementioned two-step pivoting process, theobject may be attained by a single-step pivoting process. In thisprocess, for selective turning, the stack of products in horizontalalignment is preferably gripped from below by the gripping device of anarticulated robot and pivoted through an effective angle of 180°, forinstance while it is being moved to the pallet. If the stack is not tobe turned, the stack of products in horizontal alignment may preferablybe gripped from above.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin a device for moving a stack of products using a robot, it isnevertheless not intended to be limited to the details shown, sincevarious modifications and structural changes may be made therein withoutdeparting from the spirit of the invention and within the scope andrange of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is an illustration of a preferred exemplary embodiment of adevice containing a robot for carrying out steps of a preferredembodiment of a method according to the invention;

FIG. 2 is a perspective view of a delivery of a machine for furtherprocessing;

FIGS. 3A and 3B are perspective views of preferred exemplary embodimentsof the delivery;

FIGS. 4A to 4D are perspective views of preferred exemplary embodimentsof a robot-guided gripping device;

FIG. 5 is a perspective view of a preferred exemplary embodiment of thegripping device;

FIGS. 6A and 6B illustrate preferred exemplary embodiments of depositschemes;

FIG. 7 is a lateral view of a preferred exemplary embodiment of atransport stack; and

FIG. 8 is a flow chart for illustrating a method for moving a stack ofproducts by means of a robot.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings, corresponding features have the same reference symbols.Repetitive reference symbols have sometimes been left out for reasons ofvisibility. The following is a summary list of reference numerals andthe corresponding structure used in the above description of theinvention.

Referring now to the figures of the drawings in detail and first,particularly to FIG. 1 thereof, there is shown a preferred exemplaryembodiment of a device preferably containing a robot and carrying outsteps of a preferred embodiment of the method of the invention. FIG. 1is a view from above.

A machine 70 for further processing, preferably a folder, which is onlypartly shown, is located in a position 74 and produces printed products2, preferably printed and/or folded signatures 2, which are in the formof stacks 1 of products and are moved, e.g. conveyed, in a direction oftransport 71 on a delivery 72. The action of the delivery, in particularthe conveying action, may be controlled by the digital computer 80. Astack of products preferably contains a plurality of products resting ontop of one another.

A digital computer 80, which is preferably connected to a network 81,may control the machine 70 for further processing and optionally furthermachinery; for instance, job data may be provided for the manufacturingof products. Job data may be provided via the network.

The delivery 72 may move the stacks 1 of products into a protected zone73. A robot 10, preferably a robot containing an articulated arm 11 withmultiple axes 12, for instance six axes, may be disposed in this zone.The robot may be a common industrial robot.

A gripping device 20 is disposed on the robot 10, preferably at the endof the articulated arm/“hand” 11 thereof. The gripping device may gripand hold stacks 1 of products to move them away from the delivery 72,preferably only within the protected zone. The movement 15 moves thestack 1 of products along a spatial curve to a transport pallet 62,where the stack of products is deposited and preferably positioned at adeposit location 60 in accordance with a deposit scheme 61. A number ofpallets may preferably be provided within reach of the robot. Themovement may comprise multiple movement portions 16. In between twomovement portions, the gripping device may be rotated and/or pivoted,for instance. The rotating and/or pivoting may likewise occur during themovement.

A pivoting device 40 is preferably disposed at the end of the delivery72. The pivoting device 40 may pivot the stacks 1 of products out of thehorizontal 50, a horizontal plane 53 or the horizontal position 52 intothe vertical 54, the vertical plane 57 or the vertical position 56. Thepivoting device may comprise two alignment elements 41, which arepreferably movable in a horizontal direction, and/or straighteningelements 42 for the stack of products. They may be embodied as surfaces,for instance plates.

The action, in particular the movement 15 and/or 16 of the robot 10,and/or the action, in particular the pivoting, of the pivoting device,may be controlled by the digital computer 80.

FIG. 2 illustrates a preferred exemplary embodiment of a delivery of amachine for further processing. The delivery 72 may comprise a pluralityof rollers 76. The delivery may be a roller conveyor. Some of therollers may be driven, for instance by motors 75. The digital computer80 may control the process of conveying the stacks 1 of products 2resting on top of one another. In this process, the stacks of productsmay be separated from one another in the direction of transport 71. Theproducts 2 and therefore also the stacks 1 of products that have beenformed preferably have four corners 5. Die-cut products may have morecorners. If the products are folded products, their folding edges arepreferably oriented to be parallel to the direction of transport.

FIGS. 3A and 3B illustrate preferred exemplary embodiments of thedelivery, preferably containing a pivoting device, as they carry outsteps of a preferred embodiment of the method of the invention. FIGS. 3Aand 3B are perspective views.

FIGS. 3A and 3B illustrate the end of the folder 70 and the delivery 72on which the stacks 1 of products are conveyed in the direction 71 oftransport up to a pivoting device 40 (transporting step 101). Beforebeing pivoted, the stacks of products and consequently the products 2are preferably in a horizontal position 52.

The pivoting device 40 preferably contains grippers 43, for instancebars movable relative to one another, preferably one bar (closing“hold-down element”) on one side of the stack 1 of products and threebars on the other side of the latter. The pivoting device and/or thegrippers thereof may be pivoted about a horizontal axis 51. Thegrippers, which are located below the stack 1 of products in FIG. 3A,may be positioned between the rollers 76 and may be pivoted out of thisposition.

FIGS. 3A and 3B illustrate sections of the robot 10 and the articulatedarm 11 thereof. The robot is preferably movable in a horizontaldirection on the floor and therefore positionable at various locations.The robot may, for instance, be supported on rollers. For example, railsmay be provided.

FIGS. 3A and 3B illustrate the—preferably horizontally movable—alignmentelements 41 and/or straightening elements 42.

A comparison between FIGS. 3A and 3B illustrates the pivoting movement110 through an effective angle α1 (pivoting step 110). In theillustrated example, the angle α1 is preferably 90°. After the pivotingstep, the stack 1 of products is preferably in a vertical position 56.If the products 2 are folded products, in the vertical position, thespines are preferably at the top.

FIGS. 3A and 3B illustrate two sides 3 and 4. The robot 1 may preferablygrip the pivoted stack 1 of products from side 3 or from the oppositeside 4. Side 3 may be referred to as the front side and side 4 as theback side. The selection of the side may be computer-controlled as afunction of a deposit scheme.

The pivoting device may optionally be configured for rotation and maythus be rotated about a vertical axis 55. The stack of products maypreferably be rotated through 180°. In accordance with this option, therobot 1 may always grip the pivoted stack 1 of products from the sameside, preferably from the side 3 or the front side.

FIGS. 4A to 4D illustrate preferred exemplary embodiments of arobot-guided gripping device as it carries out steps of a preferredembodiment of the method of the invention. FIGS. 4A-4D are perspectiveviews.

FIGS. 4A to 4D illustrate a flange 26 of the robot 10. The grippingdevice 20 for stacks 1 of products is preferably disposed on the flange.The gripping device is preferably disposed for rotation about an axis ofrotation 13 (rotating step 142). The gripping device is disposed topivot about a pivoting axis 14 (further pivoting step 122 or backpivoting step 123). Both the axis of rotation and the pivoting axis maybe a respective single axis 12 of the robot or respective multiple axes.

The gripping device 20 preferably contains two support arms: a firstsupport arm 21 and a second support arm 23. The support arms arepreferably perpendicular to one another. A first gripper 30 ispreferably disposed on the first support arm so as to be movable in afirst longitudinal direction 22. A second gripper 32 is preferablydisposed on the second arm so as to be movable in a second longitudinaldirection 24. The grippers may be driven by linear drives 25 to beadjusted as a function of the format.

The first gripper 30 preferably contains a first pair of gripper jaws 31including an immovable gripper jaw 31 a and a movable gripper jaw 31 b.The movable gripper jaw may be driven by a linear drive 37. The secondgripper 32 preferably comprises a second pair of gripper jaws 33including an immovable gripper jaw 33 a and a movable gripper jaw 33 b.The movable gripper jaw may be driven by a linear drive 37. Each one ofthe immovable gripper jaws may include a support element 34, preferablya support surface. The movable gripper jaws act to open and close thegrippers.

The grippers 30 and a 32 grip the stack 1 of products 2 preferably atthe corners 5 thereof and especially at corners 6 that are diagonallyopposite one another (see diagonal 7 in FIG. 5).

In the example shown in FIG. 4A, the gripping device 20 grips the stack1 of products that has been pivoted into a vertical position from side4, i.e. from the back side, for instance. In other words, when thegripping device grips the stack of products, it is preferably located onside 4. To illustrate this, the transport direction 71 is indicated.

In the example shown in FIG. 4B, the gripping device 20 likewise gripsthe stack 1 of products that has been pivoted into a vertical positionfrom side 4, i.e. from the back side, for instance.

A comparison between FIGS. 4A and 4B shows that either the one pair ofcorners 5 (top left and bottom right) or the other pair of corners 5(bottom left and top right) may be gripped. The edges may be selected ina computer-controlled way and as a function of a deposit scheme.

In the example shown in FIG. 4C, the gripping device 20 grips the stack1 of products that has been pivoted into a vertical position from side3, i.e. from the front side, for instance.

In the example shown in FIG. 4D, the gripping device 20 grips the stack1 of products that has been pivoted into a vertical position from side3, i.e. from the front side, for instance.

A comparison between FIGS. 4C and 4D in turn shows that either the onepair of corners 5 (top left and bottom right) or the other pair ofcorners 5 (bottom left and top right) may be gripped. The edges mayagain be selected in a computer-controlled way and as a function of adeposit scheme.

The decision whether the stack 1 of products is gripped from side 3 orfrom side 4 and whether the one pair of corners 5 or the other pair ofcorners 5 is gripped in this process depends on how the stack ofproducts is to be deposited: whether it is to be deposited in a turnedor unturned arrangement and whether it is to be deposited in a rotatedor unrotated arrangement. This in turn depends on a selected depositscheme and the respective deposit position within this scheme. Thedigital computer 80 controls the gripping operation and the appropriateaction of the robot 10 in accordance with the deposit scheme and depositposition. In this process, the side and the corners are selectedaccordingly.

Having been gripped and during the movement 130, in particular inbetween two movement portions 130 a and 130 b and preferably beforebeing deposited (step 152), the stack 1 of products is pivoted througheffective angle α2 —either pivoted further (step 122) or pivoted back(step 123). When it is pivoted further, the stack of products ispreferably deposited in a turned arrangement (turning step 140); when itis pivoted back, it is deposited in an unturned arrangement (non-turningstep 141).

FIG. 5 illustrates a preferred exemplary embodiment of the grippingdevice as it carries out step 150 of letting a stack of products sag inaccordance with a preferred embodiment of the method of the invention.FIG. 5 is a perspective view.

FIG. 5 shows the gripping device 20 with the two grippers 30 and 32. Thegrippers hold a stack 1 of products at diagonally opposite corners 6.The grippers are positioned/spaced apart from one another on the twosupport arms 21 and 23 as a function of the format of the stack ofproducts and in such a way that the stack of products sags (step 150 ofletting the stack sag). When the stack of products is deposited on thetransport pallet 62 or on a transport stack 64 that has already beenformed, the sagging diagonal 8 is the first part to touch the pallet/thetransport stack. This allows the stack of products to be deposited in aprecise way without disturbance and the open grippers 30 and 32 to bemoved away from the stack of products by moving them in directions 58perpendicular to one another.

The digital computer 80 may control the opening and moving away.

FIG. 5 illustrates the two immovable gripper jaws 31 a and 33 a with tworespective stop elements 35, in particular stop surfaces 35. When thestack 1 of products is deposited, the two support elements 34 (disposedbelow the stack of products and therefore not visible in FIG. 5) arepreferably oriented in a horizontal direction, whereas the respectivetwo, i.e. four, stop elements are preferably oriented in a verticaldirection. The opening and closing of the grippers and the movement ofthe movable gripper jaws 31 b and 33 b occurs in a direction 38.

FIG. 5 illustrates a sensor 66, preferably disposed on one of theimmovable (lower) gripper jaws 31 a or 33 a. The sensor may measure thedistance to the pallet or to the transport stack that has already beenformed or the height 65 and may transmit the measured value to thedigital computer 80, allowing the latter to control a precise and inparticular collision-free deposit.

FIG. 5 illustrates two further grippers 36, in particular suctiongripper 36. They are preferably used to grip and hold intermediatelayers 67.

FIGS. 6A and 6B illustrate preferred exemplary embodiments of depositschemes.

FIGS. 6A and 6B are top views of an example of twelve stacks 1 ofproducts. They were deposited in an order from stack 1 to stack 12.

At a respective corner of every stack of products, the gripping device20 and flange 26 are shown as a circle. At two respective corners, thetwo grippers 30 and 32 are shown. Each one of arrows 58 indicates thedirections into which the opened grippers are moved to release the stackof products.

Depositing the stacks 1 of products at the deposit positions 60 inaccordance with the selected deposit scheme 61 allows the grippers 30and 32 to move in the horizontal without colliding with stacks ofproducts that have already been deposited before.

As shown in FIGS. 6A and 6B, what is referred to as a “chimney” 68, anempty space in the deposit scheme, may be created.

A comparison between FIGS. 6A and 6B shows that the deposit scheme maychange. The deposit scheme is preferably changed in every new horizontalplane/layer of a transport stack to be formed. This improves thestability of the transport stack.

FIG. 7 illustrates a preferred exemplary embodiment of a transport stackcreated by the steps of “depositing”. FIG. 7 is a lateral view.

A first layer 63 of stacks 1 of products has been deposited on atransport pallet 62 in accordance with a first deposit scheme. On top ofit, an intermediate layer 67 has been deposited. The robot may takeintermediate layers off of a neighboring stack of intermediate layers.Suction grippers 36 may be used for this purpose. A second layer 63 ofstacks 1 of products is deposited on the intermediate layer inaccordance with the second deposit scheme, which is preferably differentfrom the first deposit scheme. As it can be seen, the edges of thestacks of products 1 may be horizontally offset 69 relative to oneanother. This improves the stability of the transport stack.

As the gripping device 20 approaches the transport stack 64, the sensor66 may measure the vertical distance 65 and the digital computer 80 mayuse the measured value to control the collision-free movement of thegripping device.

FIG. 8 illustrates a preferred exemplary embodiment of a flow chart.

Optional steps are indicated by dashed lines.

The processing step (100) may comprise the manufacturing of foldedproducts 2.

The transporting step (101) may comprise the transportation of stacks 1of products into a direction of transport 71.

The separating step (102) may comprise the separation of stacks 1 ofproducts in the direction of transport 71.

The stopping step (103) may comprise the stopping of the stack 1 ofproducts at a pivoting device 40.

The pivoting step (110) may comprise a pivoting of the stack 1 ofproducts 1 by means of a pivoting device 40, in particular through anangle α1=90°.

The aligning step (111) may comprise an alignment of the stack ofproducts, preferably about a vertical axis. Alignment elements 41 may beused for this purpose.

The step of straightening (112) may comprise a straightening of theproducts 2. A straightening element 42 may be used for this purpose.

The vibrating step (113) may comprise a vibration of the stack 1 andconsequently of the products 2.

The aerating step (114) may comprise an aeration of the stack 1 ofproducts. The aeration may be attained by the vibration.

The modifying step (115) may transform a fanned-out stack of products 1into an unfanned stack of products. Alignment elements 41 may be usedfor this purpose. Each one of them may be formed by a surface such as aplate with two chamfers.

The takeover step (120) may be done by the gripping device 20 and inparticular the grippers 30 and 32 thereof. In the takeover, the stack ofproducts may be transferred from the pivoting device 40 to the grippingdevice 20. The takeover may occur from side 3 or from side 4.

The holding step (121) may be done by the closed grippers 30 and 32.

The forward pivoting step (122) may be done by the robot arm 11, inparticular through α2=90°.

The back pivoting step (123) may be done by the robot arm 11, inparticular through α2=−90°.

Further pivoting or back pivoting are preferably selected as a functionof the deposit scheme.

The moving step/movement (130) is preferably done using the robot 10.

The partial moving step/movement portion (130 a) and the partialmoving/movement portion (130 b) are preferably done using the robot 10.

The calculating step (131) is preferably done using the digital computer80. The movement of the robot 10 may be calculated.

The controlling step (132) is preferably done using the digital computer80. The movement of the robot 10 may be calculated.

The turning step (140) may be done by the robot arm 11, in particularthrough α1+α2=180°.

The non-turning step (141) may be done by the robot arm 11, inparticular through α1+α2=0°.

The rotating step (142) may be done by the robot arm 11.

The sag (150) may be attained due to an adjustable distance between thetwo grippers 30 and 32.

The measuring step (151) of measuring the distance 65 and/or height 65may be done by the sensor 66.

The deposit/stacking (152) may be done by the robot arm 11. In thisprocess, a predefined deposit scheme 61 may in particular be taken intoconsideration.

LIST OF REFERENCE SYMBOLS

-   1 stack of products-   2 printed products, in particular folded printed products-   3 side-   4 opposite side-   5 corners-   6 diagonally opposite corners-   7 diagonal-   8 sagging diagonal-   10 device, in particular robot-   11 robot arm/articulated arm-   12 axes-   13 axis of rotation-   14 pivot axis-   15 movement/path-   16 part of movement/part of path-   20 gripping device-   21 first support arm-   22 first longitudinal direction-   23 second support arm-   24 second longitudinal direction-   25 linear drive-   26 flange-   30 first gripper, in particular pliers-type gripper-   31 first pair of gripper jaws-   31 a immovable gripper jaw-   31 b movable gripper jaw-   32 first gripper, in particular pliers-type gripper-   33 second pair of gripper jaws-   33 a immovable gripper jaw-   33 b movable gripper jaw-   34 support element, in particular support pad-   35 stop elements, in particular two stop surfaces-   36 further gripper, in particular suction gripper-   37 linear drive-   38 movement to open/close the grippers-   39 blower device-   40 pivoting device-   41 alignment elements-   42 straightening element-   43 gripper-   50 horizontal-   51 horizontal axis-   52 horizontal position-   53 horizontal plane-   54 vertical-   55 vertical axis-   56 vertical position-   57 vertical plane-   58 two directions perpendicular to one another-   60 deposit position-   61 deposit scheme-   62 base, in particular pallet-   63 position of already deposited stacks of products-   64 transport stack-   65 height-   66 sensor, in particular distance sensor or camera-   67 intermediate layer-   68 chimney-   69 offset-   70 machine for further processing, in particular folder-   71 direction of transport-   72 delivery-   73 protected zone-   74 position of a machine for further processing-   75 drives-   76 rollers-   80 digital computer-   81 network-   100 processing step-   101 transporting step-   102 separating step-   103 stopping step-   110 pivoting step-   111 aligning step-   112 straightening step-   113 vibrating step-   114 aerating step-   115 changing step-   120 takeover step-   121 holding step-   122 further pivoting step-   123 pivoting back step-   130 moving step/movement-   130 a partly moving step/movement portion-   130 b partly moving step/movement portion-   131 calculating step-   132 controlling step-   140 turning step-   141 step of not turning-   142 rotating step-   150 step of letting sag-   151 measuring step-   152 depositing/stacking step-   α1 (first) effective angle-   α2 (second) effective angle

1. A device for moving a stack of products, the device comprising: arobot for moving the stack of products, said robot having an articulatedarm and a gripping device for the stack of products, said grippingdevice disposed on said articulated arm, said gripping device having afirst gripper and a second gripper and wherein said first and secondgrippers are positionable relative to one another.
 2. The deviceaccording to in claim 1, wherein said first and second grippers arepositionable to accommodate predefined formats of products or stacks ofproducts.
 3. The device according to claim 2, wherein said first andsecond grippers are positionable on two ends of a selected diagonal of aselected format.
 4. The device according to claim 1, wherein said firstgripper is embodied as a first pliers-type gripper including a firstpair of gripper jaws and said second gripper is embodied as a secondpliers-type gripper including a second pair of gripper jaws.
 5. Thedevice according to claim 4, wherein each one of said first and secondpairs of gripper jaws contains an immovable gripper jaw and a movablegripper jaw linearly movable relative to said immovable gripper jaw. 6.The device according to claim 5, wherein each said immovable gripper jawhas a support element extending horizontally and at least one stopelement extending vertically.
 7. The device according to claim 6,wherein said immovable gripper jaw has: a support surface as saidsupport element, said support surface extending horizontally; and twostop surfaces as said at least one stop element, said two stop surfacesextending vertically and perpendicular to one another.
 8. The deviceaccording to claim 4, wherein the stack of products is held by saidfirst and second pairs of gripper jaws in a force-fitting/non-positiveand/or form-fitting/positive way.
 9. The device according to claim 1,further comprising at least one blower device disposed on said grippingdevice to blow air underneath the stack of products when the stack ofproducts is deposited.
 10. The device according to claim 1, furthercomprising at least one further gripper disposed on said grippingdevice, said at least one further gripper is embodied as a suctiongripper for intermediate layers.
 11. The device according claim 1,further comprising at least one distance sensor and/or at least onecamera disposed on said gripping device.
 12. The device according toclaim 4, wherein said gripping device contains a first support arm andsaid first gripper is disposed on said first support arm so as to belinearly movable in a longitudinal direction of said first support arm.13. The device according to claim 12, wherein said gripping device has asecond support arm and said second gripper is disposed on said secondsupport arm so as to be linearly movable in a longitudinal direction ofsaid second support arm.
 14. The device according to claim 13, whereinsaid first support arm and said second support arm are disposed on saidgripping device so as to be perpendicular to one another.
 15. The deviceaccording to claim 13, wherein said first and second pairs of gripperjaws are two linearly movable gripper jaws being movable in a directionperpendicular to a respective one of said first and second support arms.16. The device according to claim 1, wherein said gripping device isdisposed on said articulated arm for rotation about an axis of rotation.17. The device according to claim 16, wherein said gripping device isdisposed on said articulated robot arm so as to be pivotable about apivot axis perpendicular to the axis of rotation.
 18. The deviceaccording to claim 1, wherein said articulated arm contains six axes.19. The device according to claim 1, wherein said robot is horizontallydisplaceable relative to at least one machine for further processingthat create stacks of products.
 20. The device according to in claim 2,wherein said first and second grippers are positionable in acomputer-controlled manner.